Select XML multiple only a few nodes with the same name

Question

I'm trying to construct a soap message, and I was able to construct the entire message using a single select. Except the problem is, on only a few occasions the same node name is repeated twice.

So for example the required output result should be like so, with two separate id root nodes:

<SoapDocument>
  <recordTarget>
    <patientRole>
      <id root="1.2.3.4" extension="1234567" />
      <id root="1.2.3.5.6" extension="0123456789" />
    </patientRole>
  </recordTarget>
</SoapDocument>

I tried to use my sparse knowledge of xpath to construct the node names like so:

select
    '1.2.3.4'    AS 'recordTarget/patientRole/id[1]/@root',
    '1234567'    AS 'recordTarget/patientRole/id[1]/@extension',
    '1.2.3.5.6'  AS 'recordTarget/patientRole/id[2]/@root',
    '0123456789' AS 'recordTarget/patientRole/id[2]/@extension'
FOR XML PATH('SoapDocument'),TYPE

Apparently xpath naming can't be applied to column names id[1] and id[2] like that? Am I missing something here or should the notation be different? What would be the easiest way to constuct the desired result?

Answer 1

From your question I assume, this is not tabular data, but fixed values and you are creating a medical document, assumably a CDA.

Try this:

SELECT 
(
    SELECT
        '1.2.3.4'    AS 'id/@root',
        '1234567'    AS 'id/@extension',
        '',
        '1.2.3.5.6'  AS 'id/@root',
        '0123456789' AS 'id/@extension'
    FOR XML PATH('patientRole'),TYPE
) AS [SoapDocument/recordTarget]
FOR XML PATH('')

The result:

<SoapDocument>
  <recordTarget>
    <patientRole>
      <id root="1.2.3.4" extension="1234567" />
      <id root="1.2.3.5.6" extension="0123456789" />
    </patientRole>
  </recordTarget>
</SoapDocument>

Some explanation: The empty element in the middle allows you to place two elements with the same name in one query. There are various approaches how you get this into your surrounding tags. This is just one possibility.

UPDATE

I'd like to point to BdR's own answer! Great finding and worth an up-vote!

Answer 2

A little more elaboration on the answer from Shnugo, as it got me trying out some things using an "empty column".

If you do not give the emtpy column a name, it will reset to the XML root node. So the following columns will start from the XML root of the selection you are in at that point. However, if you explicitly name the empty separator column, then the following columns will continue in the hierarchy as set by that column name.

So the selection below will also result in the desired result. It's subtly different, but in my case it allows me to avoid using subselections.

select
    '1.2.3.4'    AS 'recordTarget/patientRole/id/@root',
    '1234567'    AS 'recordTarget/patientRole/id/@extension',
    ''           AS 'recordTarget/patientRole',
    '1.2.3.5.6'  AS 'recordTarget/patientRole/id/@root',
    '0123456789' AS 'recordTarget/patientRole/id/@extension'
FOR XML PATH('SoapDocument'),TYPE

Answer 3

This should do the job:

WITH CTE AS (
    SELECT *
    FROM (VALUES('1.2.3.4','1234567'),
                ('1.2.3.5.6','0123456789')) V ([root], [extension]))
SELECT (SELECT (SELECT (SELECT [root] AS [@root],
                               [extension] AS [@extension]
                        FROM CTE
                        FOR XML PATH('id'), TYPE)
                FOR XML PATH('patientRole'), TYPE)
        FOR XML PATH ('recordTarget'), TYPE)
FOR XML PATH ('SoapDocument');